A light-shielding border is disposed on the surface of a conventional touch panel, wherein the light-shielding border can be a black matrix photoresist layer. The black matrix photoresist layer is formed by providing a composition including carbon black dispersed within a photosensitive resist, coating the composition on a glass substrate, and subjecting the composition to a lithography process (i.e. soft baking, exposure, development, and hard baking). Although the carbon black has advantages such as low cost and high blackness, the black matrix photoresist layer including carbon black exhibits low surface resistance after hard baking at high temperatures, resulting in short circuits among wire traces disposed on the border and a distortion of the signal due to the electrical conductivity of carbon black. As such, the black colorant of the black matrix photoresist layer should be a carbon black with a highly insulative surface.
On the other hand, a hybrid carbon black such as a carbon black wrapped by a polymer film easily gels, thereby increasing the viscosity of the photoresist composition including the hybrid carbon black. Accordingly, a novel hybrid carbon black that will avoid gelling is called for.